with solder. Next, fold the strap over to position the
contact point. Wet the strap contact point with
solder, but do not solder the button yet. You want to
insure wetting on the strap first. You may need to
roughen the surface a bit.

When satisfied, quickly solder down the strap to
the button. Four hands can be a big
help! A length of tape along the strap
will hold it down. Figure 4A shows
the finished positive end of the
rebuilt pack, while Figure 4B shows
the negative end.

Testing

Measure the voltage from the
negative end to the band. It should
be 4.8V-5V depending on the charge
state. Gently fit the pack into the
battery chamber.

The fit is certain to be tighter
than the OEM battery, but it should
fit fine. Position the cut in the band
away from the internal side contact.
Press and lock the cap into position.

Your THS700 model should
power-up and run for several hours,
so test out several charge/discharge
cycles. Remember, the internal
charger does not appear to be a
“fast” charger, so allow 10 hours or
more for a full charge. Figure 5
shows the new battery pack inserted
into the scope.

Caveats

I haven’t tested the rebuilt
battery pack in a Tektronix external
charger. The batteries are not welded
together, and the external charger
applies no in-line pressure as does
the THS700.

Finally, if your pack seems stuck
in the THS700, extract by grabbing
the soldered strap with pliers.

So far, I have rebuilt two battery
packs and am very satisfied with the
3-4 hours of operational life between
charges. NV

February 2018 21

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